Imagination Machine power supply

[Judge Mental]

My cousin is selling me an Imagination Machine, but it doesn't come with a power supply. It came with an AC power supply model T-1215A, but I can't find one anywhere on the net. The connector is a 5 DIN. Is there a suitable substitute?

 

 

 

Edited May 31, 2021 by Judge Mental

[carlsson]

I found the Programming and Technical Assistance Manual online. The original site appears dead, but Archive got a copy.

https://web.archive.org/web/20191223210540/http://hcvgm.org/Static/Manuals/APF/APF_IM-1_Programming_and_Technical_Assistance_Manual.pdf

 

Chapter II (page 19) is about the MPA-10, which I believe is what we in daily speech mean by the Imagination Machine. It supposedly receives an AC voltage, which it converts into +5V DC, -5V DC, +12V DC, -12V DC (or maybe the later is GND). Appendix C (page 71) has schematics of which D-9 covers the tape/power. There is a 7812 that generates the 12V and a 7805 that generates the 5V. While I can't find the AC input, a good guess would be 9V AC IMHO. The question is if 1A = 9 VA is sufficient or if you need more than that, in particular to power the tape recorder etc.

 

A search for T-1215A didn't bring me elsewhere than the APF operations manual with illustrations of the system but no further specs on the power supply. Perhaps it isn't even rated so one could look up its specs. Perhaps by using the combined resources, some else can pinpoint you better.

[carlsson]

Ha! I found pics here.

http://www.nausicaa.net/~lgreenf/apfpage2.htm

 

So we're looking for 13.8V AC @ 1.25A. I don't know how picky it is about the voltage, if you can feed it with 12V AC and the voltage regulators will function anyway. The base unit seems to work on 9V AC @ 780 mA or more, but I understand that you need both power supplies to run this beast? I'm not sure why there is a 5-pin DIN for a single voltage AC input but perhaps it was convenient. In that case it remains checking the schematics and/or trace the wires on the PCB to see which two are active on the DIN connector.

 

I know that e.g. the Microbee 32 also has a 5-pin DIN connector on which it supplies 9V DC + GND onto two pins, one is used for composite video output and the remaining two are used for tape load/save which is a rather odd variant but I don't think the 5-pin DIN in this case would be used for anything more than power?

[Judge Mental]

2 hours ago, carlsson said:

Ha! I found pics here.

http://www.nausicaa.net/~lgreenf/apfpage2.htm

 

So we're looking for 13.8V AC @ 1.25A. I don't know how picky it is about the voltage, if you can feed it with 12V AC and the voltage regulators will function anyway. The base unit seems to work on 9V AC @ 780 mA or more, but I understand that you need both power supplies to run this beast? I'm not sure why there is a 5-pin DIN for a single voltage AC input but perhaps it was convenient. In that case it remains checking the schematics and/or trace the wires on the PCB to see which two are active on the DIN connector.

 

I know that e.g. the Microbee 32 also has a 5-pin DIN connector on which it supplies 9V DC + GND onto two pins, one is used for composite video output and the remaining two are used for tape load/save which is a rather odd variant but I don't think the 5-pin DIN in this case would be used for anything more than power?

Thanks for the info. I wonder if an adapter with a 5 DIN connection attached to one of my MP1000 wall warts would work?

[carlsson]

You have multiple power adapters for the base unit, but none for the Imagination Machine? While at first I speculated that 9V AC might be enough, I'm not entirely sure if the original power supply is rated 13.8V AC. Also you still would need to figure out which pins on the DIN connector are used. Fortunately since it is AC there is no problem with polarity, but the question is if the other pins are connected to something else or just floating. Perhaps reading the technical manual in more detail would give out more info. There may be more online resources too, though it is a quite scarce machine so most people today probably treat it as a collectable than something to tinker with.

[Judge Mental]

28 minutes ago, carlsson said:

You have multiple power adapters for the base unit, but none for the Imagination Machine? While at first I speculated that 9V AC might be enough, I'm not entirely sure if the original power supply is rated 13.8V AC. Also you still would need to figure out which pins on the DIN connector are used. Fortunately since it is AC there is no problem with polarity, but the question is if the other pins are connected to something else or just floating. Perhaps reading the technical manual in more detail would give out more info. There may be more online resources too, though it is a quite scarce machine so most people today probably treat it as a collectable than something to tinker with.

Yeah, the resources are few. Mostly historical stuff, and owners showing off their collections. Time to get creative. It's the Imagination Machine after all.